Enemy Unseen
by ii-Phoenix-ii
Summary: A serial killer terrorizes the city and a group of college students take it upon themselves to solve the murders. [Modern AU]


**Chapter 1: Krista Lenz**

 **Disclaimer:** I do not own Shingeki no Kyojin

 _I'm sorry! Instead of writing chapters for the stories I have up already I'm posting my third new Riverta story this week. But I can't help it! It's like I have a problem!_

* * *

Eren ran up the stairs, mentally cursing, feeling relieved only when he went through the door and stood in the classroom entrance. The apology on his lips for his tardiness died as he saw people turning in their papers. His best friend Armin walked up to him, an exasperated look on his face. "Really, Eren, of all days to be late you choose _today_."

"It's not my fault! I set the alarm on my phone but forgot to put the phone on charge so it died in the middle of the night." He led them in the direction of a café. They walked through the courtyard, weaving around the other students like experts. "Besides, the teacher said she'd drop the lowest score."

"You shouldn't act so flippant." Armin didn't bother to argue longer, knowing it would fall on deaf ears.

They entered aquaint little café. It was a 7 minute walk from their next class, a quiet little brown building with plenty of light, soft leather seats, and the best coffee they'd ever had. "Hey Sasha," Eren greeted her with a wave of his hand.

"Hi guys, the usual?"

"Yes, thank you," Armin nodded. He frowned, "What's wrong? You look upset."

"You haven't heard?" Sasha leaned in. "Krista Lenz was found dead last night."

"You meant _the_ Krista Lenz?" Eren's eyes widened.

"Is there any other?" Jean sneered from behind Sasha.

"Be nice to customers, Jean!"

He rolled his eyes and handed them their orders. Eren and Armin settled near the fireplace. Armin opened the newspaper he'd picked up, scanning the content quickly. "It's in the headline."

"What's it say?"

"Nothing much except that she was founded murdered in her house."

"Somebody _killed_ her?"

"Yeah, apparently it was grisly too. Her housekeeper found her and said in her statement it was so horrible she threw up."

"Who the hell would want to kill Krista?" Eren took out his phone, wishing it wasn't dead. "I mean she's like an _angel_." The blonde-haired actress always reminded him of a Golden Retriever pup with her big blue innocent eyes and baby face. "Any details on how she was killed?"

"No, but the police hinted it was incredibly horrific. I bet it's going to be all over the news for months."

"No kidding." Eren frowned, "But who'd want to kill her? She wasn't a stuck up bitch like so many other movie stars. Hell she might have been the _only_ one in the entertainment business _nobody_ hated."

Armin nodded, "It's just _wrong_."

They continued to discuss the murder until it was time to head to their next class. All throughout the day they kept hearing everyone gossip about Krista. Eren ignored the professor and whispered quietly to Armin, "I don't envy the cops."

"No doubt they'll be under a lot of pressure from the media to find the killer. It's a high profile case."

* * *

"Erwin! How nice of you to come to my lab," Hange pulled one hand out of the cadaver on the table in front of her and waved. "Tell me, what can I do for you?"

"Have you started the autopsy on Ms. Lenz?"

"Not yet. I have a few other cases I have to attend to first."

"Hange…"

"No," she said sharply. "Her death was a tragedy, no doubt. But so were theirs," Hange gestured to three other bodies. "I'm not going to put them on the backburner just because the newest one is a pretty face."

"But she's not just another pretty face. You know many movie stars use stage names, right?"

"Crap." She knew where this was going.

"Her real name is Historia Reiss, the mayor's only child— _was_ the mayor's only child."

Hange felt pity well up inside, Mayor Reiss had already lost his other children in a car accident. _And now he's lost the last member of his family in such a gruesome manner._ She shook her head at the horrible hand life had dealt him. Certainly she held no love for the man, but it was not something she'd wish on anyone.

"Don't worry about the others," Erwin mistook her headshake as a sign of refusal. "I've requested another pathologist to take over their cases."

"Very well," Hange cleaned up quickly and called Moblit, her assistant. They geared up and began the procedure. Moblit laid the body on the table, retrieving his clipboard and a black pen he nodded to Hange. "Historia Reiss, 4'9", 92 lbs, female, Caucasian, blonde hair, blue eyes. No notable birthmarks, scars, or tattoos."

The young woman was in her nightdress. Her bare skin—arms, legs, and face—was covered with burns and blisters, the red flesh was dry and cracked. Her white dress was slightly discolored. Hange checked each nail individually, hoping but not expecting to find any evidence of the attacker. "Get the plastic bags," she said to Moblit and removed the clothing, filing each piece separately.

Moblit put them away and picked up his clipboard and pen again, observing the body and taking notes as Hange spoke. "Indents on nose, bruising under the chin, and ligature marks around her wrists and ankles." Historia's body had been found bound to a chair. "No bruising or tearing in the genital area." There were no signs of sexual assault but as per protocol, she used a vaginal swab to check for semen.

"No wounds or needle marks on either side of the body," Moblit noted. Historia could have been sedated through the arm, the tiny mark hidden by the burns. Only a test of her bloodstream would reveal the truth.

"You took photos of her clothed body beforehand, yes?" Hange asked, already knowing the answer.

"Yes," Moblit nodded. He picked up the camera and began taking photographic record of the body, making sure to take close-ups of the bruises and other such marks.

Erwin continued to watch silently as the duo took a blood sample and a Cerebo-Spinal Fluid sample, and then thoroughly washed the body. They took hair samples and x-rays before starting the dissection. Hange made a Y-incision, starting from the shoulder joint down to the navel, the branches of the Y curving around under the breasts.

They cut open the ribcage and took another blood sample, directly from the heart. Moblit used a pipette to extract a urine sample. They weighed the organs, taking special care with the liver—both Moblit's preliminary COD and Hange's own theory were the same. Erwin watched Hange eagerly but patiently.

"We believe the COD is poisoning. She's got acidic burns over her body consistent with the effects of sulfuric acid, aka battery acid. The bastard used some clip to plug her nose then pushed her head up and forced her to drink the acid. Moblit's taken the liver to the toxicology lab for confirmation."

"Thank you," Erwin nodded. He checked his watch. The autopsy had taken three hours. "I have to go meet the mayor this evening; I told him I'd stay for the autopsy and bring him the results as soon as I can."

"I'll have the papers on your desk before you leave," Hange nodded.

* * *

"Eye contact is a very powerful tool. If people do it for 60% of the time during a conversation, they're bored, 80% when they're attracted to you, and 100% if they're threatening you. You can tell if someone is attracted to you because their pupils will increase in size by about 45%."

Petra took notes absent-mindedly, the sub was nice but he couldn't hold her attention for long. She pulled out her phone and read the news about the dead young actress. She rolled her eyes at the crazy theories people were posting. _They should leave the police work to the cops_. She couldn't help but thinking 'Herd instinct.'

Two weeks had passed since Krista's murder and the media was beginning to pressure the cops. _Honesty, don't they care? Do they not have enough brain cells to think about the other murder cases the cops have to deal with?_ She couldn't imagine what kind of frenzy the media would've cooked up had Krista's family come out. But there was no word from them.

She gathered her notes and went off to her favorite café. Finally, she was done for the day. The place was packed, much to her disappointment. _I like it so much better when it's quiet and unknown_. Petra blamed the free donuts, though not enough to refrain from picking up a maple bar—just as someone else was reaching for it.

"Oh, sorry."

"It's fine, you can have it," Petra pushed it towards him.

"Thanks," Oluo grinned widely.

"No problem," she shrugged and picked up a chocolate glazed one. _There's nowhere to sit_. There was only one table with empty seats. "Mind if I sit here?"

"No, go ahead."

Petra pulled out her review sheet. "Wow, you're dedicated," Armin smiled. "Eren here can learn a thing or two."

"So I miss one stupid little quiz," he rolled his eyes, "big deal."

"Lucky," Petra sighed, "I can't afford that. I'm Petra by the way, I'm a junior." They quickly introduced themselves. A minute of small talk and she started studying while the two went on to talk about the good old days.

* * *

Levi sighed, rubbing his eyes. His roommate would _not_ shut up. "Do you realize you sound like some fucking stalker?" How did he end up with _this_ idiot? He wondered if it was too late to switch out.

"I'm not a stalker! I just happened to see her—"

"And stared like some creeper I bet. You didn't secretly take photos of her, did you? As a future cop, should I feel the proper thing to do is report you?" Oluo was scandalized and Levi rolled his eyes. "You think it's true love just because she gave you a _donut_?"

"It's fate," he said convincingly.

"So if I lend you notes before a big test, does that mean you'll propose to me?" He asked disturbed.

"What? Don't be—"

"Shut up," he held up his hand, "I'm getting a call. What?" He said rudely as a greeting.

" _I have to cancel dinner this weekend, something's come up."_

"It's fine, Erwin."

" _No, it's not,"_ there was a sigh at the other end. _"It's just this case—"_

"I understand," Levi rolled his eyes. "I'm not some little brat. Anyway, good luck, you'll need it." He disconnected before Erwin could reply.

"Was it your godfather?"

"Yeah," Levi opened up his laptop. "Looks like I'm free this weekend."

"Great, then we can go to that party I told you about. You can even be my wingman."

"And do what? Watch you skulk around the punch table scaring away the girls with your old, pervy face? No thank you." He ignored his roommate's blubbering in favor of his research. Oluo eventually left and Levi got into Erwin's files.

He had seen his godfather entering the password and gotten access to the police's system ages ago. Having never encountered a hacker or any other technological problems, Erwin had never changed the password. Not that it would take Levi long to figure it out. All of his godfather's passwords were the same. Every time he created a new one, the last number would be one higher than the previous.

He opened the file on Krista Lenz's murder. _H.R? Who's that?_ He found the initials only once in the file and couldn't make the connection. Levi went through the crime scenes photos. Sometimes he found a clue the others missed and gave them an anonymous tip.

The shots were of the living room: a wide, open room with beige and lavender furniture. There was a staircase that spiraled up. The dark-brown chair Krista was tied to clashed with the color scheme. _Did he bring the chair from another room and tie her up?_ _Maybe the dining room?_ In any case, the entire house had been dusted from top to bottom but there weren't prints that didn't belong.

Krista's body showed burns—the official COD was poisoning by sulfuric acid. He checked to see what kind of knot was used to tie her up; it didn't look like any he'd familiarized himself with. The acid used was in a drain cleaner solution and available in dozens of stores across the city. So far they were still searching for anyone who'd bought the stuff within the past three months.

The list of suspects was pathetically small: zero. The only suspect, Krista's father's ex-wife, had been out of town. CCTV footage of the hotel and witnesses gave her a solid alibi. Levi closed the laptop after an hour, stretching his muscles. He grabbed his wallet and keys to get dinner. He hadn't found anything the cops had missed.

But he had learned something. Krista Lenz was an important person. The lack of parental names even in the police's report and the H.R initial meant she was some important person's kid. _Whoever they are, they don't want their names in the media for some reason_. The killer had been very efficient. There were no clues what-so-ever. Levi had a very bad feeling about this.

* * *

"Thanks for picking me up, Mikasa," Sasha pulled on her coat. "Maybe I should get a boyfriend; I wouldn't have to trouble you then."

"We're roommates anyway so it doesn't matter," Mikasa shrugged.

"There have been break-ins at the dorms in the past month and I'm worried someone might jump me. I know it's kind of silly…"

"No, there's nothing wrong with being cautious," she replied.

"How're your classes going so far?"

"They're okay; my teachers are competent and nice, guess that's all I can ask for."

"My math teacher sucks. He gives so much homework and it doesn't even match what we do in class. I mean the format of the problem is so different and confusing." They were back to their dorm room when Sasha suddenly said, "Hey, did you know Krista had a girlfriend? I mean that's what the rumors say. I think the cops are investigating her."

"I never really pay any attention to that so I don't know."

The next morning, Mikasa was stretching when Eren walked up to her. "We're sparring with partners today, wanna be my partner?" She nodded and they grabbed the protective gear. At their sensei's signal they began.

 _He's not bad_. She stopped holding back and pushed him back easily. Mikasa eased up when Eren was cornered. "You're really good," he admitted grudgingly.

"I've been doing mix martial arts since I was a kid."

"Then why are you taking this class?" The unhappy look vanished at her words. He wasn't feeling quite so sour knowing she was practically a professional.

"It's good to go back to the basics. 'Sides, I thought it might keep me motivated to continue training."

They switched partners twice. She and Levi introduced themselves and bowed before starting. Barely 30 seconds into the spar, the entire class stopped to stare, including the proctor. Each punch and kick was met with a guard and a counter.

Their teacher was just about to step in when Mikasa ended the match with a well-placed kick to Levi's solar plexus, using just enough power to knock him down. Levi was momentarily stunned but accepted her hand. Their teacher scolded them lightly but let them off with a warning.

Mikasa thought she was just pleased to see the 'beauty, power, and grace' she talked about in action. "That was _awesome_ ," Eren declared. "You must be a black belt."

"I used to take part in competitions, and it required us to stay in the best condition possible." She was happy to know her skills hadn't gotten as rusty as she had feared from the lack of use.

"I have a friend who does that. She's the best hand-to-hand fighter I've seen in my life." He glanced as Levi passed by. "I gotta say I was happy to see you win. That guy totally kicked my ass." He studied her curiously, "Both of you are 'Ackerman,' are you related?"

"No, just share the same name."

"Okay," Eren shrugged. "Hey, if you wouldn't mind, can I have your number? It'd be nice to have a training partner outside of class. My best friend is a bookworm," he rolled his eyes. "He can't even throw a punch properly."

 _He has honest eyes_. Mikasa stared at Eren's smiling face then nodded, "Sounds good."

* * *

Erwin rubbed his eyes tiredly. He went over the case files one more time, not optimistic at all. Naturally the only thing he got was a headache. _What a waste_. He put the files away and left his office. _Hopefully we'll find a lead tomorrow_. Krista's girlfriend was coming in.

And there was another problem. Erwin wondered how that tidbit of information got out. Someone had tipped the media about Krista's relationship. On top of catching the murderer he had to find out who leaked the news. He was going to have to take extreme caution. _I'll have to warn my subordinates of the consequences of giving out information_. It was going to step on toes.

Erwin shut off the light and left. He pulled out his phone to call Levi and saw the time. _2:03 am_. He was going to come in early in the morning anyway. _Is there any point in going home?_ He sniffed himself. Maybe there was a reason to go home after all. He had almost been hoping for their well-wisher to call in with a clue that might help move the investigation along.

 _Hopefully Krista's girlfriend will provide some valuable insight_. He wasn't optimistic though.

* * *

 _This is stupid._ Levi glared at the laptop screen. _Whose brilliant idea was it to invent calculus anyway?_ His thoughts were interrupted when someone spoke over his shoulder. "You're format is wrong," Armin said. He smiled apologetically. "Sorry, couldn't help myself. You mind?"

"By all means," he nudged the laptop away. "You look kind of young."

"I'm a freshman. I love math and strategy and all that." He punched in the answer and got a green check-mark. "I'm in advanced classes," he said proudly.

"Is that so?" Levi mumbled, feeling slightly jealous. _Why can't this shit come to me so easily?_

"Hey Armin," Eren wandered over, "where'd you—oh. Hey, Levi, right?" He saw the laptop and rolled his eyes. "Really, Armin? _Really_?"

"I'm sorry! I couldn't help myself."

"Well I appreciate your lack of self-control," Levi packed up his stuff. "See you around."

"You know him?

"Yeah, we have Karate together." Eren pulled out his phone.

Armin nodded, "You wanted to head for the café, right? You still owe me a—Eren?" He furrowed his eyebrows, "What's wrong?"

Eren held up his phone screen, face pale.

* * *

"What a shame," Hange murmured, reading about the young woman dead not three feet from her.

"Why are we here?" Moblit asked curiously. "There's no suicide note. As far as I can tell from her neighbors, there was no indication of suicidal thoughts or behavior either. It could have been an accident."

"It could have," Hange agreed. "We're here to confirm whether it was or not. She's young and somewhat well-known around here, so here we are."

They reached the top of the apartment complex and stared at the ground. "Somehow I get the feeling this wasn't an accident…"

* * *

 _ **Please Review~**_


End file.
